1. Field of the Invention
The present invention relates to a method of preventing corrosion of an apparatus for use in processing an article of a polyarylene thioether. More particularly, the present invention relates to a technique of preventing chemical corrosion of a processing apparatus by incorporating into the resin an anticorrosion agent which is a hydroxide or oxide of a metal of the group IIa of the Periodic Table or an aromatic carboxylic acid salt of a metal of the group IIa of the Periodic Table.
2. Description of the Prior Art
A polyarylene thioether has a higher processing temperature than that of an ordinary general-purpose resin and tends to generate a corrosive gas such as sulfurous acid gas (SO.sub.2) at a high temperature. Accordingly, a metal portion of a melt-processing machine, which comes into contact with this polymer in molten state during extrusion forming or injection molding, often undergoes corrosion. A ferrous material customarily used for an ordinary processing machine is readily corroded chemically, and a formed article of the polymer is spontaneously colored.
As a measure for solving this problem, there has been proposed a method in which corrosion of a metal is prevented by adding a hydroxide or carbonate of an alkali metal to a polyarylene thioether (as disclosed, for example, in the specification of U.S. Pat. No. 4,017,450). From the results of our research, however, it has been found that since the alkali metal salt can be dissociated into ions, if the formed article comes into contact with moisture, electrical properties (for example, insulation characteristics) and water resistance can be deteriorated, or a significant increase in the melt viscosity can be often caused.